Well, its officially Spring, and my 2005 GLS Passat TDI is only ten days past her 2nd birthday (46k mi.), so it's time for a brake system flush. I've done the obligatory forums search and found that our Jetta brethren (and sistern? I crack myself up!) are the only ones that have posted on this subject at any substantive length. Their thread on the flush DYI leaves me with some unanswered questions that may be specific to our B5's, so I post here.
I've flushed several systems, including but not limited to, my wife's MkIII Jetta, my daughter's 2001 Subbie, and my old '91 300TE 4Matic Benzo. I use a SpeediBleeder. All of these rigs were equipped with ABS and it is my understanding that in order to properly flush an ABS equipped brake system one must use 32 PSI at the master cylinder; which I've done successfully with the aforementioned beasties.
The A4 flush thread makes mention of NOT using more than 14 PSI (though DieselDorf mentions using 18 PSI with no ill effects). What's up with that? My MB Service Library specifically notes the higher working pressure. Can the systems be THAT different?
Also, there seems to be some difference of opinion on the order of caliper bleed. I've always used RR, LR, RF, LF as a method, though the A4 thread mentions the exact opposite is to be used on newer ABS equipped models. Yikes! I feel a bit like Rip VanWinkle or Alice through the looking glass. Did my nap take a bit longer than I reckoned? Did I fall down a rabbit hole?
Can someone explain what it is I've missed? Thank you in advance for your patient understanding.
Best regards,
HazenVagen

On the A4s, VW states exceeding 14 PSI (1 bar) will cause the proportioning valve inside the ABS unit to prevent a proper flushing.

A4 systems equipped with MK 60 controllers user LF, RF, LR, RR sequence. The arrangement of the pipes connecting to the controller is the reason. This sequence gets the most air (if any) out of the system first.

However, you don't have the A4 platform vehicle.

The 2004-2005 TDI Passats are different. The procedure does specify to use a pressure of at least 2 bar. Sequence is RR, LR, RF, LF.
After a normal bleed, the procedure states that a second person is needed. Then...

This bleeding sequence must be performed 5 times per brake caliper.
Bleeding sequence:
Right rear brake caliper
Left rear brake caliper
Right front brake caliper
Left front brake caliper

Vehicles with ABS, ABS/EDL, ABS/EDL with ASR or ABS/EDL with ASR and ESP.
A test drive must be performed for these vehicles after bleeding the brakes. During this, at least one ABS regulation must be performed!

Thank you, MoGolf!
Well, I did the first sequence correctly, but I did not do the second sequence. I'll do it tomorrow when I have a helper.
Whilst sitting in driveway at idle, I depressed the brake pedal and with force the pedal went to the floor a few times. I also pumped the hand brake a few times. I was a bit concerned at the way the pedal went to the floor (maybe not all the way to the stop). I cautiously backed out of my drive way and tested the brakes, The pedal got hard and the wagon quickly stopped.
I then went around the neighborhood at maybe 25 MPH and did a few stops. The pedal travelled normally (a bit less than it had been prior to the flush) and the car braked evenly and quickly. The pedal felt noticeably harder than it did yesterday.
After building some confidence I took it out for a real drive. The brakes worked flawlessly. It's raining here so I did two full panic stops from 40 and 50 MPH. Again, the brakes and ABS worked like champs with quick straight stops.
BTW that little screen filter in the top of the brake fluid reservoir is a booger to remove. I assume it's not meant to be re-used as I couldn't figure a way to get it out without damaging the POS.
Thanks again for the info, MO.
Best regards,
HazenVagen
P.S. My variant is ABS,ASR and ESP equipped.

What do those steps do that isn't done if you flush the system with a motiv brake bleeder? I'm confused. Why after power flushing the system and not letting air or anything other than fresh fluid into the system would you need to do the pump the brake pedal and bleed routine?

Quote:

Originally Posted by MOGolf

After a normal bleed, the procedure states that a second person is needed. Then...

This bleeding sequence must be performed 5 times per brake caliper.
Bleeding sequence:
Right rear brake caliper
Left rear brake caliper
Right front brake caliper
Left front brake caliper

Vehicles with ABS, ABS/EDL, ABS/EDL with ASR or ABS/EDL with ASR and ESP.
A test drive must be performed for these vehicles after bleeding the brakes. During this, at least one ABS regulation must be performed!

The second procedure that MoGolf mentions sounds redundant to me, too. When I asked the dealer service manager about it he looked puzzled and he went out to the service floor and talked to a tech. He came back and said "Never heard of it."
Who knows?
Before taking it to you dealer ask the service manager what procedure they use. If you don't get a warm fuzzy find an independent.
Don't do it yourself if you don't have a power bleeder.

What do those steps do that isn't done if you flush the system with a motiv brake bleeder? I'm confused. Why after power flushing the system and not letting air or anything other than fresh fluid into the system would you need to do the pump the brake pedal and bleed routine?

It is the procedure prescribed by VW with no explanation given. They use a pressure bleeder too.

You're just looking to be sure the fluid comes out free of air bubbles during that brake pedal process.